Hydrocarbon conversion with the hydrogenation of the cracked products



R. T. wlLsoN 3,050,457 HYDRocARBoN CONVERSION WITH THE HYDROGENATION Aug. 2l, 1962 OF THE CRACKED PRODUCTS Filed NOV. 24, 1958 vm mm1 .252mm mm1 LWN: 4 Etj .www

United States Patent Gli 3,050,457 Patented Aug. 21, 1962 ICC This invention relates to conversion of hydrocarbons, for example, mineral oils. In one of its aspects, the invention relates to the conversion of a residual oil having a high sulfur content and containing metal contaminants, which ordinarily are undesirable on the conversion catalyst, under conditions so as to cause the formation of sufficient hydrogen to in a unitary, highly economical, operation reform, desulfurize, hydrogenate and otherwise improve the liquid conversion products obtained during said conversion. In another of its aspects, the invention relates to a process for cracking a high sulfur residuum to produce a desirable sulfurand olefin-free product which comprises cracking in a so-called fluid catalytic cracking operation, in the presence of a cracking catalyst, a high sulfur residuum under conditions to convert at least 50 percent thereof per pass to distillate liquid, carbon and hydrogen in an amount sufficient to remove sulfur and olelins from said liquid in a hydrogenation step, recovering hydrogen and said liquid from the cracking efuent and passing said liquid and hydrogen to a hydrogenation zone under hydrogenation conditions, maintaining said liquid and said hydrogen in said hydrogenation zone under said hydrogenation conditions until a desired sulfur and ole-iin removal has been accomplished and then recovering the so-treated liquid from said Zone. In a further aspect, the invention relates to the conversion or upgrading of a heavy residuum in the presence of a catalyst having. an unusually high metals contamination, say, in the range OOO-25,000 p.p.m. to produce liquid products and hydrogen containing gases which sufce to desulfurize at least the LPDO-1,017.5 F. boiling range fraction of said liquid products to yield rened liquid product having a low sulfur content, of the order of about 01.7 weight percent.

The predominant use of off-gas in a typical renery is either as a fuel or as a source of H2 for hydrotreating processes. In many present-day processes, the hydrogen produced in catalytic reforming operations is used to hydrotreat reformer feed stocks. ln most instances, the reformer hydrogen will supply most feed stock pretreatment needs. However, there are instances in Which the hydrogen requirements are not met by reforming alone. For example, the calculated hydrogen production as a result of reforming the 20G-400 F. fraction containing 39% naphthenes from a Middle East crude is 940` cubic feet per barrel of crude charge. Experimentally from the same stock only 720 cubic feet of H2 per barrel were produced. Catalytic reforming of the 20G-400 F. should, as calculated, produce 113,500 cubic feet of hydrogen. However, only 87,000 cubic feet actually are produced. This amount of hydrogen is not enough to desulfurize the 400-1,025 F. fraction containing 2.40 Weight percent sulfur or 7.48 lb. sulfur per barrel of distillate. These figures are tabulated below.

lveight Vol, vWeight LbSJ Wafra crude percent percent .API percent gal.

sulfur C4 and lighter 1. 35 2.17

5-20 2.5i 3.47 84.3 2004100o F. 10. a4 12. 06 53.0 0 9s 6.385 4001,025 F 4s. 70 49. 30 27. 4 2. 40 7. 415 1,025 R+.-. 37. 20 33. 00 6. 3 4. 91 7, 583

Hydrogen production-Reforming 20G-400 F. fraction based on 1,000 barrels of crude charged per day.

Hydrogen produced:

940 cubic feet/barrel-calculated 720 cubic feet/ barrel-actual 113,500 cubic feet/ day-calculated 87,000 cubic feet/day--actual Hydrogen required for removal of S from 4001-1,025 F. fraction:

147,900 cubic feet/ day for complete removal 123,000 cubic feet/day required for 83% S removal Thus, it is seen that, using the above charge stock, even reforming does not produce enough hydrogen to desulfurize the 400-l,025 F. fraction. Therefore, another source of hydrogen .is needed. Such an additional source of hydrogen could `be manufactured hydrogen. The cost of manufactured H2 is from 150 to 200 dollars per million standard cubic feet.

lt is an object of this invention to provide a process for the conversion of hydrocarbons. It is another object of this invention to convert a high sulfur residual oil in the presence o-f a catalyst in a manner to provide in a unitary operation for the refining or' liquid products obtained during said conversion. It is 'another object of this invention to so operate a catalytic cracking conversion as to produce during said conversion gases and liquid products, the gases being of character and amount sufficient to refine said liquid products. It is fa further object of this invention to provide a unitary hydrocarbon conversion process for the upgrading of heavy high sulfur content residual oils, such as heavy Wafra residuum,

The residuum to which this operation :is particularly adapted has the following characteristics:

l have now found that by converting a residual oil, as herein set forth and characterized, under conditions to obtain `at least percent and preferably of the order of or 60 percent conversion, I can produce liquid product and hydrogen containing gases in an amount suliicient to hydrotreat the liquid product to produce a highly desirable final liquid product without having recourse to external hydrogen.

Thus, according to the present invention, there is produced a desuliurized, stable distillate by subjecting a high boiling, high sulfur residuum, to fluid catalytic cracking to form a hydrogen-rich gas, residuum-free liquid and carbon and then hydrotreating the liquid product thus obtained "with hydrogen-rich gas to remove the sulfur and oletins. Still further, according to the invention, the catalyst which is used is one containing a fairly high quantity of metal contaminants which iare laid down on the catalyst by the oil |being converted and such a catalyst can have the following compositions, among others:

Sulfur resistant halloysite percent 40 Filtrol 58 do 60 NiO p.p.m 1,160 V205 p.p.m 1,230 Iron oxide p.p.m 86- supported on silica-alumina having a composition of 13 percent alumina and 87 percent silica.

Area: 96 square meters per gram, and- Filtrol 58 (montmorillonite clay) percent 100 Alumina do 13 Silica do 87 Metals V205 and NiO` p.p.m 3,300

It has been found in uid catalytic cracking tests with 1,025 F.4-Wafra residuum (5 percent sulfur) over a 40-60 percent conversion range that suicient hydrogen can be yielded at 60 percent conversion to satisfy the hydrogen requirement for hydrotreatment of total liquid eilluent while at 40 percent conversion sufficient hydrogen is yielded to satisfy hydrogen requirement for hydrotreatment of the 400 F24- cycle oil. Thus, according to the invention, the catalytic cracking severity can be adjusted so 4that, the catalytic cracking hydrogen yield and hydrotreating hydrogen requirement are in balance, resulting in an optimum yield of low sulfur distillate without use of outside hydrogen.

The following data are pertinent to show hydrogen requirement for sulfur removal as against hydrogen yield at various extents of conversion.

[Fluid catalytic cracking of 1,025 F. plus Wafra res.]

Conversion of 400 F.i,1 vol. percent- 59. 9 52.0 46. 3 40. 4 Yield of feed:

H2, eu. ft./bbl 343 208 187 133 (3l-Gi, Weight percent 12.0 9.7 9.1 7. 3 (l5-400 F., vol. percent 31. 7 37.4 24. 9 23. 0 400 E+, vol. percent-. h 40.1 48.0 53.7 59. 6

t l st de osits wei t pe Chitty. ig 23.3 22.1 19.6 18.3 Sulfur lb. bbl.:

G5400/C F o. 47 o. 45 o. is o, 44 400 F,+ 5. 72 6.31 7.00 8. 51

[Hydrogen requirement for complete sulfur removal,z cu. ft./bbl.]

-400 F 19 18 18 18 iiiof R+ 229 252 28o 34o Total 248 270 298 358 1 To catalyst deposits and materials boiling below 400 I". 2 Assume 40 eu. ft. hydrogen consumed/lb. sulfur removed.

t has been round and this is a particularly very advantageous feature of the presen-t invention that, as the degree of conversion is increased, the hydrogen make is increased as well as `finding a decrease in sulfur present in the 400 F;+fraction. This is shown in the foregoing table in which at 40.4 percent conversion the pounds per barrel of sulfur are 8.51 while at 59.9 percent conversion this figure is reduced to 5.72, the hydrogen make having increased from 133 at 40.4 percent conversion `to 343 cubic feet per barrel, respectively.

Thus, `the inventio-n provides an operation in which a Middle East crude residuurn which ordinarily is extremely diftcult `to treat advantageously is treated, as claimed. This treatment results in various advantages, some of which are evident upon a study of this disclosure, the drawing and the appended claims.

Referning now to lthe drawing, there is shown diag-rammatically an operation according to the present invention. The drawing is now described in connection with a specific operational example.

Example 318,700 pounds per dayof 1,025 F.+residuum from Wafra crude having an API gravity of 6.3 is charged via liquid hourly space velocity of 1 and a gas circulation line 1 yto 'a catalytic residuurn cracker 2. Cracker 2 is 10 pounds p.s.i.g., 892 F., a space velocity of 1.18 and a residence time of 10 minutes. The catalyst is a silicaalumina cracking catalyst con-taining 87 percent silica and 13 percent alumina. Mean weight of carbon on the catalyst is about 2.38 weight percent. Fifty pounds of steam per bar-rel of feed are charged to the unit. Conversion obtained is 60 percent. 245,400 pounds per stream day are yielded from the cat cracking operation and are passed via line 3 to flactionator 4 wherein C2 and lighter material-s and H28 pass roverhead through line 5 into fractionator 33. Fractionator I33 operates as a `deethanizer with ethane and lighter together with H28 passing overhead through line 11 and C3 and C4 materials passing out as a bottom `fraction through Aline 10. A C5 and heavier fraction is removed from fractionator 4 and passed to fractionator 7 via line 6 and in the amount of 194,407 barrels per stream day. Fractionator 7 operates to remove overhead, through line 8, 73,938 barrels per stream day of material boiling in the C5-400" F. range and 120,469 barrels per stream day of 400 F.4- is removed via line 9. 21,897 pounds per stream day of `C2 and lighter and H28 are passed through line 121 to compressor 5.2 wherein they are compressed to 600 p.s.i.g. and are thence passed by line y13 to a H25 removal unit 14 wherein 9,911 pounds of H28 are removed overhead via line 34. C2 and lighter material which has had H28 removed is passed via line 31 and line 32 to hydrotreate-rs 15 and 16. The net gas make resulting from the operation of the residuum cracker 2 is 730 cubic feet per bar-rel of feed charged, having a composition of 5 6 mol percent hydrogen, 26 mol percent methaneand 18 mol percent ethane. 73,938 pounds per stream day of C5-400 F. 4is charged to hydrotreater 15. This stream contains .565 weight percent sulfur, has a brornine number or" 106, a refractive index of 1.4242 at 20 C., a research octane number of 93.8 with 3 m1. of TEL and an API gravity of 57.1. Hydrotreater 15 is operated to produce a gasoline having a sulfur content of 0.1 weight percent or less. Conditions in the hydrotreater 15 are 600 p.fs.i.g., 650 F., a liquid hourly space velocity of 5 and a hydrogen charge of 2,000 cubic feet per `barrel of hydrotreater feed with a net hydrogen consumption of 87 cubic feet per barrel of residuurn cracker feed required to remove sulfur and olens to the desired degree. The effluent from hydrotreater i5 is removed to high pressure liquid gas separator 18 which is operated at 500 pounds pressure and wherein ethane and lighter are passed via line 35 to recycle compressor 36 `and thence to line `13 and H28 removal unit 14. The liquid phase from the liquid gas separator 18 passes 'through -line 21 and pressure reduction valve 22 through which pressure is red uced to 10 p.s.i.g. and enters an atmospheric pressure liquid gas separator'26 "where a further separation is made of light gaseous material and product naphtha. The gas removed by this pressure reduction operation is recycled vla line 30 to line 5. Product naphtha contains 0.095 wt. percent S and is removed via line 27 in the amount of 73,938 pounds per stream day. Returning -to fractionator 7, 120,469 barrels per stream day of material boiling above 400 F. are passed via line 9 into hydrogen treater 16. This material has a sulfur content of 4.2 weight percent, a pour point of +15 F., an anilne point of 78.6, an API gravity of 14.3 and Va BMC 1 of 83.39. Ethane and ylighter material enter hydrotreater 16 via line 32 and line 9 and this hydrotreater is operated to reduce the sulfur content to 0.75 weight percent or less. r[he hydrogen required to removed sulfur Vand olens to the desired extent .is 207 cubic feet per barrel of feed. The operating conditions Vof hydrotreater 16 are 750 F., 600 p.s.i.g., a

rate :of 2,000 cubic feet per barrel. The 400 F.{- material is removed from the hydrotreater `16 via line 17 to a 1 Bureau of Mines Correlation Index.

high pressure liquid gas separator 19 operated at 500 pounds per square inch wherein gaseous material is removed via iiue 20 to` line 35 yand recycle compressor 36. rllhe net gas product as a result of the operation of the cat cracker is 730,000 cubic yfeet per streamr day of which 320,880 is H2 yof which 294,000 consumed. The recycle rate is maintained at 1,500,000 cubic feet per day. Product distillate is removed from high pressure separator 19 via line Z3 and passes through a pressure reduction 'Valve 24 through which pressure is reduced to l0 pounds per square inch and thence into a low pressure separator wherein a separation is made between product distillate and the light gaseous material. Product distillate in the amount of 120,469 pounds per stream day containing .714r `weigh-t percent S is removed via line 23 and the gaseous material is removed overhead via line Z9 and passes to line and is recycled via line 30 to fractionator 33 via line 5.

It will be noted by one skilled in `the art in possession of this disclosure that whereas ordinarily process condi tions are adjusted to make a maximum 'amount of product distillate with a minimum amount of gas, the present invention Ideparts `from this practice to accomplish its advantageous results.

A particular-ly important and advantageous feature of the process of this invention is that the fuel gas produced from the process, though it is produced in a somewhat lesser amount, has a higher Btu. content than that obtained from the conversion operation. The following table `gives lthe principal constituents of the original gas composition and the gas composition vafter the hydrotreating operation.

Mol percent Btu/cu. ft.

Original gas composition:

56 26 669 02H5 18 Gas composition after hydrotreating:

n the rollowmg tabulation are shown conditions and ranges of conditions applicable in `this invention in the various aspects thereof. it will be understood by one skilled in the art that the invention is Ilimited only as expressed in the claims appended hereto.

CATALYTIC CRACKING Rango 80G-1,000 I". 0.3-5 t./sec. Subatmosphcrlc-l() p.s.i,g. -400 mesh.

CRUDE CHARGE TO CAT CRACKER IBP Weight percent, Metals, p.p.m

-l,l50 F. (l1-8%. 5-500.

The ranges suitable for use in the hydrotreater are as follows:

Catalysis which can be used for hydrotreating in this invention are those which .are known in the 'ar-t which are capable of catalyzing :this step and include cobalt molybdate, molybdena-alumina, and tungsten and nickel sulfides. A catalyst which is considered particularly applicable is that described in Serial Number 668,926, tiled July l, 1957, now Patent No. 2,953,515, by William C. Lann-ing. This catalyst comprises the oxides of vanadium, cobalt and molybdena deposited on porous active alumina.

From the foregoing, it is evident that the invention in its several aspects provides the art with a modus operandi and process whereby in a highly economical and eicient manner a very diicultly treatable heavy residuum material, such as Wafra 1,025 F.-{-residuum, can be advantageously processed to form desirable products without recourse to external hydrogen and, therefore, even `at a place where external hydrogen is not readily available.

rThe charging stock to which this invention is particularly applicable has been indicated to be a heavy residuum. However, the invention is applicable to topped crudes or residuums from any type of crude. However, in terms of API gravity, a crude fraction having a gravity ranging from 5 or less to 30 API can be used and the extent of conversion will depend upon the feed stock. Thus, when charging a stock having a fairly low sulfur content, the distillate produced will contain a quantity of sulfur such that at the lower extent conversion, sufficient hydrogen will beproduced for hydrotreating purposes. Thus, when less hydrogen is required to accomplish the desired hydrotreatment, a conversion level which is lower than that required in the case of a higher sulfur content will be employed.

Reasonable variation and modification are possible within the scope of the foregoing disclosure, drawing and the appended claims to the invention, the essence of which is that a high sulfur containing heavy oil is cracked to an extent of conversion such that there is obtained a gas containing hydrogen sufficient to hydrotreat the liquid products obtained from` said conversion or at least a portion thereof to obtain a distillate material having a low sulfur content and a low olelin content, if any, in the now best mode of operation employing a cracking catalyst which has purposefully been allowed to become highly contaminated with metal contaminants.

I claim:

l. A process for cracking a. high sulfur residuum to produce a desirable sulfurand olefin-free product which comprises cracking said residuum in a iluid catalytic cracking operation, in the presence of a cracking catalyst having a quantity of metal contaminant, at a temperature in the range of about G-1000" F., and at a pressure not in excess of p.s.i.g., to convert at least 30 percent thereof per pass to produce a distillate liquid and hydrogen in an amount suicient to remove sulfur and olelins from. said liquid in a hydrogenation step, recovering said liquid from the cracking eilluent, separating said liquid into a rst stream of C5 to 400 F. fraction and a second stream of 400 F. plus fraction, passing said first stream to a rst hydrogenation Zone, passing said second stream to a second hydrogenation zone, recovering hydrogen from said cracking eluent and passing a portion of the hy drogen thus recovered to said rst hydrogenation zone, operating said irst hydrogenation zone under first reaction conditions so as to elfect the desired sulfur and olefin re- LHSV moval, passing a second portion of the recovered hydrogen to said second hydrogenation zone, operating said second hydrogenation zone under second reaction conditions so as to eiect the desired sulfur and olefin removal; said rst reaction conditions comprising a temperature in the range of about 50G-800 F., a pressure in the range of about 150-1500 p.s.i.g., and a liquid hourly space velocity in the range of about lato 25; said second reaction condition comprising a'temperature on the order of at least about 100 F. higher than the temperature of said iirst reaction condition, a pressure in the range of about 150- 1500 p.s.i.g., and a liquid hourly space velocity in the range of about 1 to 25.

2. A process according to claim 1 wherein the conversion per pass is in the range of 30-60 percent and wherein the extent of conversion is made dependent upon the sulfur content of the charging stock used in the process.

3. A process for cracking a high sulfur crude to produce a `desirable sulfurand olelin-free product which comprises cracking in a fluid catalytic cracking operation, in the presence ot a cracking catalystk having a quantity of metal contaminant, at a temperature in the range of about 8001000 F., at a pressure not in excess of about y150 p.s.i.g., and at a liquid hourly space velocity in the range of about 0.3 to 5 feet per second, a high sulfur residuum obtained from said crude to convert at least 30 percent thereof per pass to produce a distillate liquid, and to produce hydrogen in an amount suiiicient to remove sulfur and oletins from said liquid in a subsequent hydrogenation step, recovering said liquid from the cracking efuent and passing said liquid to a 'hydrogenation zone, recovering hydrogen from said cracking effluent and passing the hydrogen thus recovered to said hydrogenation zone, the hydrogen thus recovered being substantially the only source of hydrogen for said hydrogenation zone, operating said hydrogenation Zone at a pressure in the range of about 150 to about 1500 p.s.i.g., at a temperature in the range of about 500 to about 800 F., and a liquid hourly space velocity in the range of about 1 to about 25; until a desired sulfur and olefin removal has been accomplished, and recovering the thus treated liquid Y from said hydrogenation zone.

4. A process for cracking a high sulfur crude to produce a desirable sulfurand oletin-free product Which comprises cracking in a fluid catalytic cracking operation, in the presence of a cracking catalyst having a quantity of metal contaminant, at a temperature in the range of aboutV 800-1000 F., at a pressure not in excess of about 150 p.s.i.g., and at a liquid hourly space velocity in the range ofrabout .0.3 to 5 feet vper second, a high sulfur residuum obtained from said crude to convert at least 30 percent thereof per pass to produce a distillate liquid, and to produce hydrogen inV an amount suiiicient to remove sulfur and olens from said liquid in a subsequent hydrogenation step, recovering said liquid from the cracking eiliuent and passing said liquid to a hydrogenation zone, recovering hydrogen from said cracking eiiiuent and passing the hydrogen thus recovered to said hydrogenation zone, the hydrogen thus recovered being substantially the only source of hydrogen for said hydrogenation zone, operating said hydrogenation zone at a pressure in the range of about 500 to about 750 p.s.i.g., at a temperature in the range of about 650 to about 750 F., and a liquid hourly space velocity in the range of about 1 to about 5; until a desired sulfur and olen removal has been accomplished, and recovering the thus treated liquid from said hydrogenation zone.

5. A process for cracking a 1025 F. plus residuum from Wafra crude to produce a desirable sulfurand olefin-free product which comprises cracking in a uid catalytic cracking operation, in the presence of a silicaalumina cracking catalyst, at a temperature in the range of about S00-l000 F., at a pressure of approximately 10 p.s.i.g., at a liquid hourly space velocity in the range of about 0.3-5 ft./sec., and a residence time of approximately ten minutes, a 1025 F. plus residuum from Wafra crude to convert approximately percent thereof per pass to produce a distillate liquid and hydrogen in an amount suflicient to remove sulfur and olefins from said liquid in a hydrogenation step, recovering said liquid from the cracking eilluent, separating said liquid into a iirst stream of C5 to 400 F. fraction and a second stream of 400 F. plus fraction, passing said first stream to a first hydrogenation zone, passing said second Stream to a second hydrogenation zone, recovering hydrogen from said cracking eiuent and passing a portion of the hydrogen thus recovered to said first hydrogenation zone, operating said first hydrogenation zone at a pressure of approximately 60() p.s.i.g., at a temperature of approximately 650 F., and at a liquid hourly space velocity of approximately 5 to produce a product having a sulfur content of approximately 0.1 Weight percent or less, passing a second portion of the recovered hydrogen to said second hydrogenation zone, operating said second hydrogenation zone at a pressure of approximately 600 p.s.i.g., at a temperature of approximately 750 F., and at a liquid hourly space velocity of approximately 1 to produce a product having a sulfur content of approximately 0.75 weight percent or less. Y

References Cited in the le of this patent 

1. A PROCESS FOR CRACKING A HIGH SULFUR RESIDUUM TO PRODUCE A DERIRABLE SULFUR- AND OLEFIN-FREE, PRODUCT WHICH COMPRISES CRACKING SAID RESIDUM IN A FLUID CATALYST CRACKING OPERATION, IN THE PRESENCE OF A CRACKING CATALYST HAVING A QUANTITY OF METAL CONTAMINANT, AT A TEMPERATURE IN THE RANGE OF OF ABOUT 800-1000* F., AND AT A PRESSURE NOT IN EXCESS OF 150 P.S.I.G., TO CONVERT AT LEAST 30 PERCENT THEREOF PER PASS TO PRODUCE A DISTILLATE LIQUID AND HYDROGEN IN AN AMOUNT SUFFICIENT TO REMOVE SULFUR AND OLEFINS FROM SAID LIQUID IN A HYDROGENATION STEP, RECOVERING SAID LIQUID FROM THE CRACKING EFFLUENT, SEPARATING SAID LIQUID INTO A FIRST STREAM OF C5 TO 400* F. FRACTION, AND A SECOND STREAM OF 400* F. PLUS FRACTION, PASSING SAID FIRST STREAM TO A FIRST HYDROGENATION ZONE, PASSING SAID SECOND STREAM TO A SECOND HYDROGENATION ZONE, RECOVERING HYDROGEN FROM SAID CRACKING EFFLUENT AND PASSING A PORTION OF THE HYDROGEN AND THUS RECOVERED TO SAID FIRST HYDROGENATION ZONE. OPERATING SAID FIRST HYDROGENATION ZONE UNDER FIRST REACTION CONDITIONS SO AS TO EFFECT THE DESIRED SULFUR AND OLEFIN REMOVAL, PASSING A SECOND PORTION OF THE RECOVERED HYDROGEN TO SAID SECOND HYDROGENATION ZONE, OPERATING SAID SECOND HYDROGENATION ZONE UNDER SECOND REACTION CONDITIONS SO AS TO EFFECT THE DESIRED SULFUR AND OLEFIN REMOVAL; SAID FIRST REACTION CONDITIONS COMPRISING A TEMPERATURE IN THE RANGE OF ABOUT 500-800* F., A PRESSURE IN THE RANGE OF ABOUT 150-1500 P.S.I.G., AND A LIQUID HOURLY SPACE VELOCITY IN THE RANGE OF ABOUT 1 TO 25; SAID SECOND REACTION CONDITION COMPRISING A TEMPERATURE ON THE ORDER OF AT LEAST ABOUT 100* F. HIGHER THAN THE TEMPERATURE OF SAID FIRST REACTION CONIDTION, A PRESSURE IN THE RANGE OF ABOUT 1501500 P.S.I.G., AND A LIQUID HOURLY SPACE VELOCITY IN THE RANGE OF ABOUT 1 TO
 25. 